In a statement, AT&T Mobility and Consumer Markets President and CEO Ralph de la Vega said that with more than twice the number of smartphone customers as its nearest competitor, AT&T is “committed to offering great value and choice for customers who want to talk, text and surf on the nation’s fastest 3G network.”

Feature phone customers can choose unlimited talk for $69.99, and Family Talk customers can get unlimited talk for $119.99 per month. All AT&T smartphone customers, including iPhone users, can buy unlimited voice and data for $99.99.

Texting remains unchanged at $20 for unlimited individual plans or $30 for Family Talk plans.

Both Verizon and AT&T said existing customers can change to any of their new plans without penalty or a contract extension.

Verizon Wireless sparked the latest price wars Friday by announcing new unlimited voice calling plans. The carrier also said that all 3G multimedia phones now will require a $9.99 per month data package, which was introduced last year for the LG enV Touch and the Samsung Rogue.

Amid the machinations between Verizon and AT&T, Sprint didn’t waste any time to point out that its price plans are even lower. Sprint says its Everything Data plans offer a savings of nearly $240 per year versus Verizon’s new Nationwide Talk & Text plans plus unlimited data package, and when family plans are compared, Sprint can offer savings of nearly $600 on unlimited messaging and data.

Telecom analyst Jeff Kagan said the new plans spell good news for consumers. “We are seeing another price war break out in wireless,” he says. “This is not the first, and it won't be the last.”

The question is whether unlimited data plans in the future will carry lower or higher prices, he says. “Some say these plans are going to come down in price, welcoming in new groups of users. Others say these low-priced plans are only to get the customer all jazzed up with using these services, then the price will go up. … What will really happen? I expect competitive pressure will keep prices dropping, but we'll have to wait and see how it unfolds.”